Abstract
Deformation of polymer separators for Li-ion batteries has been studied under biaxial tension by using a dome test setup. This deformation mode provides characterization of separator strength under more complex loading conditions, closer representing deformation of an electric vehicle battery during crash event, compared to uniaxial tension or compression. Two polymer separators, Celgard 2325 and Celgard 2075 were investigated by deformation with spheres of three different diameters. Strains in separators were measured in situ by using Digital Image Correlation (DIC) technique. The results show consistent rupture of separators along the machine direction coinciding with areas of high strain accumulation. The critical first principal strain for failure was independent of the sphere diameter and was determined to be approximately 34% and 43% for Celgard 2325 and Celgard 2075 respectively. These values can be taken as a criterion for internal short circuit in a battery following an out-of-plane impact. A Finite Element (FE) model was built with the anisotropic description of separator behavior, derived from tensile tests in orthogonal directions. The results of simulations predicted the response of separator rather well when compared to experimental results for various sizes of rigid sphere.
| Original language | English |
|---|---|
| Pages (from-to) | 139-145 |
| Number of pages | 7 |
| Journal | Journal of Power Sources |
| Volume | 378 |
| DOIs | |
| State | Published - Feb 28 2018 |
Funding
This research at Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725 , was sponsored by the Vehicle Technologies Program for the Office of Energy Efficiency and Renewable Energy ( VT1201 21105 ) and by the National Highway Traffic Safety Administration (DOE No. 2088-A031-15 ). Rick R. Lowden is acknowledged for his assistance and expertise in setting up the experiments. Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | DE-AC05-00OR22725 |
| Office of Energy Efficiency and Renewable Energy | VT1201 21105 |
| Oak Ridge National Laboratory | |
| National Highway Traffic Safety Administration | 2088-A031-15 |
Keywords
- Li-ion battery
- Mechanical abuse
- Safety
- Separator
